Generally, semi-automatic weaponry enables firing of a cartridge each time the trigger is depressed Such weapons are sometimes referred to as "self-firing". A manual loading weapon, on the other hand, requires appropriate manipulation of the weapon before successive cartridges may be discharged.
A variety of guns using discharged compressed gas for firing relatively fragile projectiles are known employing manual, semiautomatic, and fully automatic arrangements. Compressed gas powered guns are typically useful as tranquilizer guns and pellet marking guns, commonly called paint ball guns. Paint ball marking guns have attained widespread use in a recreational sport known as paint ball warfare, an activity which has captured the imagination of many adults. Typically located in open spaces with varying types of terrain, opposing sides employ guerilla-type strategy to seek out and "kill" one another by marking the opposition with a paint ball. Marking guns are also used to segregate cattle within a herd and for a variety of other purposes.
Marking guns use compressed gas to fire a gelatinous capsule containing a marking material. The marking capsules typically enclose a mixture of water and vegetable coloring so they are not toxic and can be removed from clothing and other surfaces with simple water washing. The capsule breaks on impact with the target dispersing the material to mark the target, for example an opposing player, where hit by the capsule. However, the marking capsule must have sufficient rigidity to avoid breakage during loading and firing operations of the gun.
While various types of manual loading paint ball guns, as well as automatic weapons which fire multiple paint balls upon depression of a trigger are known, the semi-automatic weaponry presently available to paint ball sportsmen and other marking gun enthusiasts, while it may perform satisfactorily under certain circumstances, is overly complex and inefficient. Known semi-automatic firing arrangements typically operate using a "blow-back" method wherein a first source of compressed gas discharges the projectile and a second source of compressed gas operates to return the firing mechanism of the gun to a ready-to-fire position. These devices and methods, however, require considerable compressed gas both to fire and to recoil the firing mechanism of the gun. In addition, such complex firing arrangements are often difficult to operate and maintain and suffer frequent breakdowns after extended periods of use.